dealer vs trader

dealer and trader both are nouns.

Word	Noun	Adjective	Verb	Adverb
dealer	Yes	No	No	No
trader	Yes	No	No	No

As nouns, dealer and trader are synonyms defined as:

dealer and trader: someone who purchases and maintains an inventory of goods to be sold

Other synonyms of dealer include bargainer, monger.

dealer (noun)	trader (noun)
a firm engaged in trading	someone who purchases and maintains an inventory of goods to be sold
a seller of illicit goods
the person who distributes the playing cards in a card game
someone who purchases and maintains an inventory of goods to be sold
the major party to a financial transaction at a stock exchange; buys and sells for his own account